You need to be careful WHO you buy from. I'm starting to see a lot of stuff about fake silver coins and bullion bars - basically a thin layer of silver, correctly embossed over a tungsten "slug" (tungsten weighs nearly the same as silver).
A good place, FAR from the scammers in NYC is Apmex.com. They're in the midwest and are one of the oldest precious metals dealers in the US. They sell pretty much everything. And no, you don't need a fancy coin or bar. An industrial silver bar, as long as its .999 purity or better works just as well and may well be cheaper because its plain wrapper - just silver.